RNU2-2

Chr 11ADAR

RNA, U2 small nuclear 2

Also known as: DEE119, RNU2-2P, RNU2B, U2

This gene encodes the U2 small nuclear RNA, which is an essential component of the spliceosome that removes introns from pre-mRNA transcripts during RNA processing. Mutations cause developmental and epileptic encephalopathy 119, characterized by early-onset seizures and developmental delays affecting the central nervous system. The condition follows an autosomal dominant inheritance pattern.

ResearchSummary from OMIM

ResearchGenerating clinical summary…

Splicing / LOFmechanismAD/AR

Clinical Summary— RNU2-2

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Gene-Disease Validity (ClinGen)

developmental and epileptic encephalopathy 119 · ADStrong

Strong evidence — appropriate for clinical testing

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Some data sources returned errors (2)

gnomad: Error: Gene not found

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD

Constraint data not available from gnomAD.

Mechanism of Pathogenicity

Splicing / LOFvariant-dependent

Non-coding U2 spliceosomal snRNA (not a protein — gene-level protein-mechanism predictors do not apply). Heterozygous de novo variants (e.g. n.4, n.35) cause a dominant developmental and epileptic encephalopathy, thought to act by disrupting spliceosome function (aberrant splicing via altered U6/branch-site interactions) rather than haploinsufficiency. Separately, biallelic variants cause a clinically distinct — and notably prevalent — recessive disorder through loss of function: they destabilise the snRNA and reduce U2-2 expression by >90%. Mechanism is therefore variant- and zygosity-dependent.

References: PMID 40909831, PMID 40950445

Expert-curated annotation. Non-coding RNA gene — protein-based mechanism predictors (Badonyi & Marsh) do not apply.